Piston problems

[OU812]

Posting a picture of both pistons that seized the one on the right happened just after I bought the quad, the other after a a couple days of riding. They appear to be damaged in the same ares on both sides. I took off the exhaust port and there was no gasket between the exhaust flange. What do you think can cause this kind of wear?

 

[blasterdude14]

have you looked inside the cylinder to see what it is like on the inside? have you checked for air leaks? there are plenty of factors to consider with this issue

 

[OU812]

The cylinder was bored to match the piston when I rebuilt the top end. It was honed and chamfered. I haven't checked for air leaks yet i need to replace some gaskets and rebuild top end again. I'll rebuild the bottom end as well I guess.

 

[blasterdude14]

You always wanna check for air leaks especially after the top end has been off, also have you checked the crank? It may be possible that the rod is slightly bent causing it to rub on the side of the cylinder

 

[killer454]

are you still running the automatic oil injector on this blaster? if YES
if you are you better check it i dont think it is working.

how long did it run after the rebuild

you have a injector problem not working or way to lean or rod or crank bearings bad.

 

[OU812]

The top ends been rebuilt a few times. It has the oil injector blocked off and i mix 32:1. Open air box, k & n, pro-circuit pie, 300 main jet. I think it's time to rebuild the whole thing when my wallet allows me. Was thinking about using some liquid gasket along with the new gaskets to help seal things up better.

 

[scotj77]

are you breaking those pistons in before riding hard there is a diy on the exact way to break in your new piston. it looks like you are overheating due to an air leak would be my guess. I have seen that exact problem on my piston when i had an airleak. it overheats and the side's where the wrist pin is swells the largest because it is thickest there. that is why it seizes on the sides like that. LEAK DOWN TEST! that should tell you where the problem is. don't just go globbing liquidgasket on to guess where the problem is. find it and fix it right

 

[phragle]

looks like a '4 corner sieze' usual culprit is not proprly warming the bike up or to tigh clearance